Abstract:

The movement characteristics of overlying strata at combined mining work face was studied with the method of field measurement of deep base point，taking the combined mining work face of a coal as a case to measure the related data. Through displacement and speed analysis of the measured results，it was found that the overburden movement form is generally non-uniform sink overall motion after the work face was mined, the rock fracture gap within the drop is small, and the surface does not appear evident large fall break. The absolute displacement of overburden is increase gradually from surface to the roof of coal bed，and the initial displacement of surface occurs in the front of work face，but the initial displacement of inner rock occurs at the back of work face，and the movement speed is non-uniform phase distribution. There is a clear permanent abscission layer in the overlying strata after mining，and the total layer is about 36% higher than the mining height. These results have certain significance as offering a theoretical basis for the study of movement characteristics of overlying strata at combined mining work face

Key words: field measurement, overburden movement, non-uinform sink, forever ionospheric